wrong
0
1
2
3
4
5
6
7
8
9
10
11
12
right
59
58
57
56
55
54
53
52
51
50
49
48
47
score 100.0 98.3 96.6 94.9 93.2 91.5 89.8 88.1 86.4 84.7 83.1 81.4 79.7
Soil Analysis
Group Name
Name _____________________________________
Today you will test some soil for five characteristics: soil texture, acidity, nitrogen
content, phosphorus content, and potassium content. These characteristics determine how well
plants will grow in a particular soil.
Soil Texture
Soil Source _____________________
The texture of a soil determines the amount of air and water the soil can hold. Plant roots
need liberal supplies of both.
Air is critical as a source of oxygen gas and as a repository for excess carbon dioxide gas.
These gases are needed for and produced by respiration in root cells, respectively. If there is not
much air space in the soil, then roots "suffocate" because they cannot carry out respiration. The
roots then die, the plant wilts, and then dies. Large soil particles do not pack tightly and therefore
provide air spaces in the soil. On the other hand, soil consisting of extremely fine particles packs
tightly and permits little air in the soil to support root function.
Water from the roots is the supply of this important chemical for the shoot system (stem,
leaves, flowers, fruits, and seeds). The water is a reactant in photosynthesis and a product of
respiration. Water makes up about 90% of plant cells by weight, and is the critical solvent in the
cell. The evaporation of water through the stomata in the epidermis of the shoots cools the plants
and prevents overheating. A soil with very large particles drains too extensively and plants will
lack sufficient water, will wilt, and perhaps even die. A soil with extremely fine particles holds
tremendous amounts of water and can hold so much as to exclude air from the soil. In that case,
the roots die, the plants wilt, and perhaps will die as well.
Thus, the perfect soil texture for growing plants is a compromise between fine particles
(clay), medium particles (silt), and coarse particles (sand). The range of soil textures that support
plant growth are called "loam."
A. AT LEAST FIVE HOURS BEFORE LAB! Fill a 100 mL graduate cylinder to the 70 mL
mark with sifted soil. Fill the cylinder with sodium hexametaphosphate (surfactant) solution
(2 teaspoons of Calgon per quart). Cover the top of the cylinder with plastic wrap. Stir/agitate
the soil completely and thoroughly so that there is no unmixed soil at the bottom of the
cylinder. Top-off the cylinder with surfactant. Continue inversion-stirring for at least five
minutes. Label the cylinder with your group name. Set the cylinder aside until the next class
meeting in a place where it will not be disturbed.
B. On the regular Lab Exercise day, and disturbing the cylinder as little as possible, measure the
volume of the sand layer in the bottom of the cylinder. Since this is the coarsest particle size,
it will have dark voids between particles (ask your instructor to help you distinguish the sand
from the silt).
Volume of the sand layer ________ mL
C. Determine the volume of the sand + silt layers. The measuring line will appear just below the
clay layer which is very smooth and usually light in color. Silt has a few voids and the
particles are visible; clay has no voids and the particles are too small to be visible.
Volume of the sand + silt layers ________ mL
D. Determine the volume of the sand + silt + clay layers. The measuring line will appear between
the clay layer and the dark water above it.
Volume of the sand + silt + clay layers ________ mL
/4
Page 2
E. Calculate the volume of the silt layer by subtracting the number from part B above from the
number in part C above.
Volume of silt layer ________ mL
F. Calculate the volume of the clay layer by subtracting the number from part C above from the
number in part D above.
Volume of clay layer ________ mL
G. Rinse out your cylinder completely and thoroughly as described by the instructor. Dry it with a
paper towel, and return it to the proper location.
H. Calculate the percentage contribution for each of the three layers by dividing their individual
volumes by the total soil volume (D). If your calculations are correct, the sum of these
percentages should be 100! Check your work!
Sand ______%
Silt ______%
Clay ______%
Total ______%
G. Place a small X on the diagram below where the three layer percentages would plot out
together. What is the texture classification for this soil?
100 0
90
10
80
70
___________________________
20
30
clay
60
Percent Clay
50
40
sandy
clay
silt y
clay
40
30 sandy
clay
clay
0
100
silt y loam
loam clay
60
loam
70
loam
20
10
Percent Silt
50
80
silt
loamy sandy
loam
sand sand
loam
90
silt
100
90
80
70
60
50
40
30
20
10
0
Percent Sand
/10
Page 3
Soil Acidity (pH)
The amount of acid or alkalai in the soil determines the availability of many nutrients for
plant growth and maintenance. It is important that the soil have the correct balance of acid and
alkalai for the amount of nutrients to be released from the soil particles for their use. The balance
is measured on a scale of acidity called pH. The scale goes from 1 (very acid) to 14 (very
alkaline) with the neutral pH of 7 in the middle of the scale. Distilled water has a pH of 7,
vinegar is typically pH 4, and soap has a pH of about 10. If the pH of soil is too high or too low,
the nutrients are either locked onto the soil particles or are washed out of the soil by rain. Even
applications of fertilizer to such a soil are useless and wasted.
Most plants grow best when the soil pH is between 5.5 and 6.5 (on the slightly acid side
of neutral). If soil tests too low, the pH can be raised by applying lime (calcium and magnesium
compounds). If soil tests too high, the pH can be lowered by applying sulfur or aluminum sulfate.
You will use a commercial soil test kit to determine the pH of your soil sample. The
instructor will dissolve two capsules of pH test powder into 10 mL of distilled water to make the
pH test reagent for the class.
A. Put your group symbol on the cap of the microfuge tube.
B. Using a drinking straw, place 0.25 mL of sifted soil into the microfuge tube.
C. Add 1 mL of the pH test reagent.
D. Close the cap and mix the contents of the tube by shaking it for 1 full minute.
E. Centrifuge the tube for 30 seconds at 14,000g.
F. Compare the color of the transparent solution above the soil layer with the pH color chart
Circle the pH indicated next to the color swatch matching most closely the color of the
solution:
7.5
7.0
6.5
6.0
5.5
5.0
4.5
G. Calculate the type and amount of soil additive needed to adjust a 50 ft. x 100 ft. garden of the
soil you sampled to pH 6.5. Assume it takes 68 lbs. of ground limestone per 1000 sq. ft.
to raise the pH 1 unit. Assume it takes 15 lbs. of aluminum sulfate per 1000 sq. ft. to
lower the pH 1 unit. If your soil test indicates the pH is already 6.5, then do the
calculation below assuming your results were pH 5.5 instead.
Name of Additive needed _________________________________
pH change needed ______ units
Amount of additive to use on 1000 sq. ft. to change to pH 6.5 _______ lbs.
Area (=width x length) of 50' x 100' garden __________ sq. ft.
Amount of additive to use on 50' x 100' garden _______ lbs.
/6
Page 4
Nitrogen Content
An appropriate supply of nitrogen gives plants healthy dark-green foliage. It promotes the
growth of vegetative parts of the plant (root, stem, leaf). It should be abundant for crops like
grass, cabbage, asparagus, onions, lettuce, and spinach. Too much nitrogen, however, can cause
growth to be too rapid, can cause the plant to grow tall and soft, to fall over, and can reduce
yield. Excess nitrogen can also delay and prevent flower and fruit formation in other crops.
Therefore, you must compromise between the high nitrogen levels needed for true vegetables and
the lower amounts needed for fruit crops (beans, corn, squash, peas, strawberries, etc).
Plants lacking sufficient nitrogen will be short, thin, and yellowish green, particularly in
the lower leaves. The leaves will turn yellow, and will brown down to a crispy state. In
monocots, such as grasses, the tip of the leaf browns first and the browning progresses toward the
leaf sheath.
The instructor will dissolve two capsules of Nitrogen test powder into 5 mL of distilled
water to make the Nitrogen test reagent for the class.
A. Put your group symbol on the cap of a microfuge tube.
B. Using a drinking straw, place 0.5 mL of sifted soil into the microfuge tube.
C. Add distilled water from the red wash bottle to reach the 1.5 mL mark.
D. Close the cap and mix the contents of the tube by shaking it for 1 full minute.
E. Centrifuge the tube for 30 seconds at 14,000g.
F. Disturbing the liquid as little as possible, transfer 0.5 mL of the clear liquid above the soil
layer into a glass 13x100 mm test tube.
G. The instructor will add 0.5 mL of Nitrogen test reagent to your glass tube.
H. Cover the glass tube with a bit of plastic film and shake it for 1 minute.
I. Let the tube stand in the test-tube rack for 10 minutes for full color development.
J. Compare the magenta color of the solution to the Nitrogen color chart. Locate the color swatch
matching most closely the color of the solution. Circle the corresponding amount of
Nitrogen needed for your soil (lbs/1000 sq ft) in the chart below:
N4 Surplus
N3 Sufficient
N2 Adequate
N1 Deficient
N0 Depleted
0.07
0.15
0.3
1.4
2.7
K. Calculate the amount of fertilizer (Ammonium nitrate = 33 percent nitrogen content) needed
for your 50' x 100' garden.
Divide the amount circled above
by the percentage of N in fertilizer (0.33) = ________ lbs Ammonium nitrate/1000 sq ft
Amount of Ammonium nitrate to buy for your whole garden: ________ lbs
/3
Page 5
Phosphorus Content
Phosphorus is essential for flower, fruit, and seed production. It is an important part of
DNA (the genetic molecule). It also facilitates seed germination. The supply of phosphorus
determines, in part, the rate that the plants reach sexual maturity. It is usually difficult to have too
much phosphorus because the supplies in soil are typically so limited.
Plants lacking sufficient phosphorus usually have purplish leaves, petioles, and stems.
They grow slowly and mature very late in the season (if then). The yield of crops like corn,
beans, peas, squash, cucumber, etc. will be very low under phosphorus deficiency.
The instructor will dissolve two capsules of Phosphorus test powder into 5 mL of distilled
water to make the Phosphorus test reagent for the class.
A. Put your group symbol on the cap of a microfuge tube.
B. Using a drinking straw, place 0.5 mL of sifted soil into the microfuge tube.
C. Add distilled water from the red wash bottle to reach the 1.5 mL mark.
D. Close the cap and mix the contents of the tube by shaking it for 1 full minute.
E. Centrifuge the tube for 30 seconds at 14,000g.
F. Disturbing the liquid as little as possible, transfer 0.5 mL of the clear liquid above the soil
layer into a glass 13x100 mm test tube.
G. The instructor will add 0.5 mL of Phosphorus test reagent to your glass tube.
H. Cover the glass tube with a bit of plastic film and shake it for 1 minute.
I. Let the tube stand in the test-tube rack for 10 minutes for full color development.
J. Compare the blue color of the solution to the Phosphorus color chart. Locate the color swatch
matching most closely the color of the solution. Circle the corresponding amount of
Phosphorus needed for your soil (lbs/1000 sq ft) in the chart below:
P4 Surplus
P3 Sufficient
P2 Adequate
P1 Deficient
P0 Depleted
0.2
0.4
0.8
1.6
3.2
K. Calculate the amount of fertilizer (Superphosphate = 18 percent phosphorus content) needed
for your 50' x 100' garden.
Divide the amount circled above
by the percentage of P in fertilizer (0.18) = ________ lbs Superphosphate/1000 sq ft
Amount of Superphosphate to buy for your whole garden: ________ lbs
/3
Page 6
Potassium Content
Potassium is important for carbohydrate (sugar and starch) manufacture by plants. When
sufficient potassium is available, plants produce stiff, erect stems, and the plants are more disease
resistant. When insufficient or excess potassium is in the soil, plants contain too much water, are
susceptible to frost injury, and growth is reduced. Since roots are important storage areas for
carbohydrate, root crops like carrot, turnip, and radish and tuber crops like potatoes are enhanced
by supplemented potassium.
Plants with deficient potassium have mottled, spotted, or streaked leaves. The leaves curl
strongly at the ends. The leaf margins die and flake out, leaving a ragged edge. Poor root
development may lead to the plant toppling over as the stem grows.
The instructor will dissolve two capsules of Potassium test powder into 5 mL of distilled
water to make the Potassium test reagent for the class.
A. Put your group symbol on the cap of a microfuge tube.
B. Using a drinking straw, place 0.5 mL of sifted soil into the microfuge tube.
C. Add distilled water from the red wash bottle to reach the 1.5 mL mark.
D. Close the cap and mix the contents of the tube by shaking it for 1 full minute.
E. Centrifuge the tube for 30 seconds at 14,000g.
F. Disturbing the liquid as little as possible, transfer 0.5 mL of the clear liquid above the soil
layer into a glass 13x100 mm test tube.
G. The instructor will add 0.5 mL of Potassium test reagent to your glass tube.
H. Cover the glass tube with a bit of plastic film and shake it for 1 minute.
I. Let the tube stand in the test-tube rack for 10 minutes for full color development.
J. Compare the amber color of the solution to the Potassium color chart. Locate the color swatch
matching most closely the color of the solution. Circle the corresponding amount of
Potassium needed for your soil (lbs/1000 sq ft) in the chart below:
K4 Surplus
K3 Sufficient
K2 Adequate
K1 Deficient
K0 Depleted
0.2
0.4
0.9
1.7
3.4
K. Calculate the amount of fertilizer (Potassium Sulfate = 50 percent potassium content) needed
for your 50' x 100' garden.
Divide the amount circled above
by the percentage of K in fertilizer (0.50) = ________ lbs Potassium Sulfate/1000 sq ft
Amount of Potassium Sulfate to buy for your whole garden: ________ lbs
/3
Page 7
Using Other Single Fertilizers
The calculations you have performed for your 50' x 100' garden were based upon use of a
single fertilizer that contained an abundance of a single nutrient (N, P, or K). These calculations
allow you to optimize the amount of each of the nutrients for your particular soil. It also turns out
that this is probably the most inexpensive way to fertilize, providing you have learned how to do
the calculations. Most people do not have the knowledge to do the calculations, and many do not
live near agricultural supply companies (there is just one in the Willimantic area). How would
the calculations be different if you had to use a different single fertilizer?
Amount circled on Amount needed per Amount needed for
Single Fertilizer
a previous page
1000 sq ft
50x100 ft garden
Nitrate of Soda 16%N
Triple Superphosphate 46%P
Muriate of Potash 60%K
Page 4:
Page 5:
Page 6:
Using “Balanced” Fertilizers
“Balanced” fertilizers contain a mixture of all three major nutrients (N, P, and K). The
amount of each nutrient in the mixture is shown on the packaging as the guaranteed analysis.
By law, the sequence of numbers in the analysis is always the percentage of N-P-K. So a
fertilizer with an analysis of 5-10-15 contains 5% N, 10% P, and 15% K. Various combinations
of nutrients are available. Repeat your calculations but this time imagine you are a sheep farmer:
Amount circled on a Amount needed per Amount needed for
Sheep Manure
previous page
1000 sq ft
50x100 ft garden
Page 4:
0.8%N
Page 5:
0.3%P
Page 6:
0.9%K
Obviously it is quite unlikely that a single amount of sheep manure will perfectly balance
your soil nutrients, but a person might choose to apply the greatest amount shown above, hoping
it is not too much of an overdose of the other nutrients.
Using Commercial “Balanced” Fertilizers
At a garden store, you can purchase a box of fertilizer that has the guaranteed analysis of
6-12-10. Repeat your calculations using this commercial fertilizer:
Amount circled on a Amount needed per Amount needed for
6-12-10 Fertilizer
previous page
1000 sq ft
50x100 ft garden
%N
%P
%K
Page 4:
Page 5:
Page 6:
/30
Page 8
Here is a listing of other fertilizers that might be less-expensive than boxed blends:
Material
Animal Tankage
Bloodmeal
Bone Meal
Castor Pomace
Cocoa Shells
Coffee Grounds (dried)
Cottonseed Meal
Cow Manure
Legume Waste
Fish Scrap
Fly Ash
Granite Dust
Greensand
Mineral Phosphate
Guano
Chicken Manure
Horse Manure
Hoofmeal and Horndust
%N
8
15
4
5.5
2.7
2.0
8.0
0.6
3.0
8
0
0
0
0
12
1.1
0.7
12.5
%P
20
1
25
1.5
1.5
0.3
2.5
0.2
0.5
13
0
0
1.5
29
8
0.8
0.3
1.5
%K
0
0.5
0
1
2.7
0.5
1.5
0.5
2
4
12
5
7
0
3
0.5
0.6
0
Material
Incinerator Ash
Milorganite
Sodium Nitrate
Peanut Shells
Phosphate Rock
Pig Manure
Seaweed
Sheep Manure
Slag
Sludge
Steer Manure
Sugar Wastes
Ammonium Sulfate
Super Phosphate
Tobacco Stem Powder
Triple Super Phosphate
Urea
Wood Ashes
%N
0.2
6
16
3.6
0
0.5
1.5
0.8
0
6
0.8
0
21
0
3.3
0
45
0
%P
5
3
0
0
30
0.3
1
0.3
8
3
0.3
8
0
18
0
47
0
1.5
%K
2
0
0
0
0
0.4
5
0.9
0
0
0.4
0
0
0
7.0
0
0
8
Here is a listing of plants (by category) to tell of their fertilizing needs:
L=low M=medium H=high VH=very high
Flowers, perennials,
bulbs & herbs
Amaryllis
Bleeding Heart
Lily of valley
Parsley
Coreopsis
Gardenia
Daffodil
Ageratum
Candytuft
Snapdragon
Tulip
Alyssum
Begonia
Bell Flower
Calendula
Canna
Carnation
Clematis
Coleus
Columbine
Cone Flower
Crocus
Dahlia
Day Lily
Foxglove
Gaillardia
Geranium
Gladiolus
Gypsophila
Hibiscus
Hollyhock
Hydrangea
Larkspur
Loosestrife
Marjoram
Mint
Nasturtium
Pansy
Peony
Perwinkle
Petunia
Phlox
Poinsettia
Poppy
Primrose
Verbena
Violet
Yucca
Chrysanthemum
Iris
Zinnia
N
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
P
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
K
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
pH
5.0-6.0
5.0-6.0
5.0-6.0
5.0-7.0
5.5-6.5
5.5-6.5
6.0-6.5
6.0-7.0
6.0-7.0
6.0-7.0
6.0-7.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.8-8.0
6.8-8.0
6.8-8.0
Shrubs, ornamentals, etc.
Camellia
Azalea
Rhododendron
Junipers
Yew
Grass
Barberry
Bayberry
Boxwood
Butterfly Bush
Cotoneaster
Euonymus
Forsythia
Lilac
Privet
Rose
Spirea
Wisteria
N
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
P
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
K
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
pH
4.0-5 5
5.0-6.0
5.0-6.0
5.5-7.0
5.5-7.0
6.0-7.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
Trees
Mountain Ash
Hemlock
Holly
Magnolia
Pine
Spruce
Oak, White
Beech
Dogwood
Oak, Red
Spruce, Colorado
Arborvitae
Maple
Redbud
N
M
L
L
M
L
L
M
M
M
M
L
L
M
M
P
L
L
L
L
L
L
L
L
L
L
L
L
L
L
K
L
L
L
L
L
L
L
L
L
L
L
L
L
L
pH
4.0-5.0
5.0-6.0
5.0-6.0
5.0-6.0
5.0-6.0
5.0-6.0
5.5-7.0
6.0-7.0
6.0-7.0
6.0-7.0
6.0-7.0
6.0-8.0
6.0-8.0
6.0-8.0
Fruits &
vegetables
Potato
Strawberries
Potato, Sweet
Apples
Bean
Carrot
Eggplant
Corn, Sweet
Beet
Watermelon
Broccoli
Cabbage
Pumpkin
Tomato
Brussels Sprouts
Cauliflower
Lettuce
Onion
Pea
Radish
Asparagus
Blackberries
Canteloupe
Cucumber
Grape
Squash
Spinach
N
M
M
L
M
L
M
H
H
H
M
H
H
H
M
H
H
H
H
M
M
VH
L
M
H
M
H
VH
P
H
M
M
L
M
H
H
H
VH
M
H
H
H
VH
H
H
VH
H
H
VH
H
L
M
H
M
VH
VH
K
H
M
H
L
M
H
H
H
H
M
H
H
H
VH
H
VH
VH
H
H
VH
VH
L
M
H
M
VH
VH
pH
4.5-6.5
5.0-6.0
5.0-7.0
5.5-6.5
5.5-6.5
5.5-6.5
5.5-6.5
5.5-7.5
5.8-7.0
6.0-7.0
6.0-7.0
6.0-7.0
6.0-7.0
6.0-7.0
6.0-7.5
6.0-7.5
6.0-7.5
6.0-7.5
6.0-7.5
6.0-7.5
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.0-8.0
6.4-7.0
If you had no soil test results to help
you determine which fertilizer to use, a
good "shot in the dark" for general
purpose would be 20-20-20 (a balanced
fertilizer). For your vegetable garden 510-5 would be generally useful, but for
fruit crops 5-15-5 would be better. For
your lawn 20-5-5 or 20-0-0 would be
appropriate. Understand however, that
fertilization without a soil analysis can
waste time, effort, and money, and is
likely to not produce ideal conditions.
Your local agricultural extension
service can perform soil analyses for a
modest fee. For this area UCONN is the
appropriate contact.